This invention is related to apparatus for removing individual sheets from the top of a stack of metal sheets which may be non-magnetic.
Stacks of magnetic sheets are commonly used in various industries, such as the automotive industry, where they are individually removed from the top of a stack and transferred to a stamping press or other metal forming apparatus.
The conventional approach for destacking magnetic sheets is to use vacuum cups to raise the top sheet from the stack. See for example, U.S. Pat. No. 3,409,149, which was issued Nov. 5, 1968, to Pierre Graux for "Apparatus for Removing Ferromagnetic Sheets Singly from a Stack". Other forms of sheet pickup devices may be found in U.S. Pat. No. 2,338,050, which was issued Dec. 28, 1943, to George E. Nelson and Carl E. Magnus for "Sheet Supporting Means for Tin Plate Sheet Feeders"; U.S. Pat. No. 2,661,948, which was issued Dec. 8, 1953, to William G. Montgomery for "Sheet Pickup and Feeder"; U.S. Pat. No. 3,224,757, which was issued Dec. 21, 1965, to Franklin E. Parke and Hugh Ross for "Magnetic Sheet Transferring Apparatus"; U.S. Pat. No. 3,584,866, which was issued Jun. 15, 1971, to Hugh Ross and Franklin E. Parke for "Magnetic Conveyor"; U.S. Pat. No. 3,682,469, which was issued Aug. 8, 1972, to Yohnosuke Itoh et al. for "Device for Handling Plates with Smooth Surface"; U.S. Pat. No. 4,067,458, which was issued Jan. 10, 1978, to Franz Schneider et al. for "Apparatus for the Unstacking and Transportation of Blanks".
Aluminum stampings, in some applications, are replacing steel stampings, but are not suited for magnetic type destacking devices. The destacking problem occurs for both magnetic and non-magnetic sheets because a thin film of oil between the sheets creates an adhesion condition which makes it difficult to raise one sheet from a vertical stack of sheets.
Consequently, aluminum sheets are manually separated sheet by sheet. Mechanical devices have met with limited success.